Segmental cable



D. 16, 1947. 5 G. w. zlNK 2,432,603

` SEGMENTAL CABLE Filed March 17, 1944 /5- PA Pff? MPE GEORGE W/L/ ARDZ/N/f ATTORNEY Patented Dec. 16, 1947 SEGMENTAL CABLE George WillardZink, Bridgeport, Conn., assignor to Phelps Dodge Copper ProductsCorporation. Dover, Del., a corporation of Delaware Application March17, 1944, Serial No. 526,949

3 Claims. (Cl. 174-110) particularly those used for alternating currentsand more particularly to stranded conductors of such largecross-sectiona1 area that, without my invention, the skin-effect wouldbe undesirably great.

Heretofore skin effect has been overcome to a large degree by the use ofsegmental construction with the addition of conductively inactive coppershielding tapes. One of the objects of my invention is to eliminate thenecessity of using these electrostatic shielding tapes which have beenthe cause of great difficulty in the manufacture of these cables becauseof the tendency of the tapes to wrinkle.

This invention is a particular form of the well known type of conductorcommercially known as segmentaL wherein the conductor is made up ofseveral stranded sectors, usually three or four, slightly insulated fromone another abut designed lfor operation as a unit.

sector but the several sectors of which the cableis composed are alsoassembled in helical lay to obtain flexibility.

My invention consists, in the addition to the above construction, of anoutside overall layer of wires which serves the triple purpose ofcarrying current, binding the sectors together and bridging the valleysbetween the outer corners of the Y sectors.

The foregoing and other features of my invention will now be describedin connection with the accompanying drawings forming part of thisspecification in which I have represented my segmental cable in itspreferred form after which I shall point out in the claims thosefeatures which I believe to be new and of my own invention.

Referring to the figure. there is shown a single conductor cable incross-section, composed of four sectors, II, I2 I3 and I4. In mypreferred construction, I apply a thin layer of insulation, such as asingle paper tape, I5 and I6, over diametrically opposite sectors, IIand Il. Over this group is a layer, I1. oi' wires applied either in ahelical lay opposite in direction to the lay of assembly of the sectors,or with a shorter lay in the 2 same direction, the purpose, in eithercase being to enable the outer wires to cross the valleys 20 betweensectors.

This conductor may be part of an insulated cable, in which case therewill be a layer of insulation I8 and, if desired, a protective coveringor sheath I9.

I may `also apply vconducting or semi-conducting shielding over theassembled conductor and/0r insulation.

The advantages of my construction are that it combines the well knownlow skin effect advantages of the so-called segmental constructionwithout the addition of conductivity inactive copper shielding tapes, ashitherto used to bridge the valleys of the sectors; that it overcomesthe undesirable tendency of tapes to wrinkle, especially where theycross the valleys and thereby cause high local dielectric stresses, andthat it eliminates the tendency of sectors to slide upon one anotherlaterally especially in the four sector construction. The outer layer ofwires, in my construction, by bridging the valleys, makes shieldingtapes unnecessary, and the solidity ofthe outer layer of wireseffectively stops lateral sliding of the sectors. However. one or morepaper binder tapes may be used to hold the sec' tors together beforeapplication of the outer layer. Such tape or tapes may or may not beremoved, depending on the size of the conductor, as the outer layer isbeing applied.

A further advantage is that larger conductors may be built than hithertobecause the limit has been set by the size of sector that could be used.

The plication of an outer layer of wires enables his limit to beconsiderably raised.

I regard my construction as applicable to bare or insulated cables orstation busses, but believe it to be particularly adapted to highvoltage insulated cables, due to its normal surface and lack ofdistortion in bending.

I wish it distinctly understood that my segmental cable hereinabovedescribed and illustrated is in the form in which I desire to produce itand that changes or variations may be made as may be desirable withoutdeparting from the salient features of my invention and I thereforeintend the following claims to cover such modifications as actually fallwithin the lines of invention.

. I claim:

1. An electric cable comprising a single round conductor, the conductorcomprising a plurality of sectors cabled in a helical lay. each sectorcomprising a number of helically laid bare wires. the

sectors having rounded corners, leaving valleys where they meet and alayer of helically laid indlvidually bare wires enclosing all thesectors to form a circular cross-section applied with its lay oppositeto the lay of the assembly of the sectors so as to bridge the aforesaidvalleys.

2. An integral electric cable comprising the conductor of claim 1,insulation and protectivei covering or coverings.

3. An integral electric cable comprising the 10 conductor of claim 1,conductor shielding, insulation and protective covering or coverings.

i GEORGE WILLARD zum. A REFERENCES CITED The following references are ofrecord in the 111e of this patent:

OTHER REFERENCES Publication, Electrotechnische Zeitschrift 61." Jahrg.Heft 9, dated Feb. 29, 1940, page 219. (A copy in class 174-129.)

